Drying apparatus



Patented Dec. 22, 1942 DRYING APPARATUS Milton E. Hanson, Haddonfield,N. J., assignor to B. F. Sturtevant Company, Boston, Mass.

Application October 21, 1939, Serial No. 300,651

3 Claims.

This invention relates to drying apparatus and relates more particularlyto dryers using heated air for drying web material such as fabric, paperand the like.

It is the practice to pass sheet or web material such as paper or cloththrough a dryer; to blow heated air upon the surface of the web, and torecirculate for reasons of economy, the air back through the heater andblower. In the past,

however, a great deal of the heated air escaped with the web leaving thedryer.

The present invention provides a compact, highly efllcient dryer fromwhich a minimum of heat escapes.

A feature of the invention resides in providing nozzles with slotsextending cross-wise the web to be dried and in providing platesextending at right angles to the web, between and beyond the nozzles,and inclose proximity to the web. The plates efiectively scrape off theair which ordinarily adheres due to surface tension, to the moving weband which ordinarily escapes from the dryer. The plates also providepassages for conducting the air back to the blower and heater where itis mixed with fresh air and applied again to the web. The plates also incooperation with the nozzles provide turbulence in air flow thusexpediting the drying action through breaking up the insulating air filmwhich heretofore has adhered to the moving web.

Another feature of the invention resides in ar ranging a blower and airheater upon the casing of an insulated web drying chamber and insupplying heated air near the center of the chamber and withdrawingrecirculated air at the nozzle ends.

An object of the invention is to improve the efliciency of web dryers.

Another object of the invention is to conserve the heated air used in aweb dryer.

Another object of the invention is to reduce the space required for webdryers.

Other objects of the invention will be apparent from the followingdescription taken with the drawing.

The invention will now be described with rei erence to the drawing, ofwhich:

Fig. 1 is an elevation view partially in section of a dryer embodyingthis invention, with section taken along lines ll of Fig. 2;

Fig. 2' is a sectional view along the lines 2-2 of Fig. 1;

Fig. 3 is an enlarged view of the plate adjusting mechanism of Fig. 2,and

Fig. 4 is an end view of the plate and adjusting screw of Fig. 2.

The blower 5 and the heating chamber 9 are mounted on the upper side ofthe casing ti and serve to supply heated air therein. The blower 5 drawsfresh air past the damper 6 through the inlet 1, and recirculated airfrom the recirculated air chambers 8, moves the mixed air through theheating chamber 9, and discharges it through. the outlet I I into theplenum space I2 above the lips l3, forming nozzles, for projecting theheated air at high velocity against the web 14.

The plates l5 extend cross-wise the dryer between the nozzle dischargeslots formed by the adjacent nozzle lips l3, and extend, as shown byFig. 2, beyond the web I4 and the nozzles on each side thereof, andcross-wise the bases of the recirculated air chambers 8. The web movesthrough the dryer on the rollers 26, as shown by Fig. 1.

The plates l5 may be raisedand lowered as shown by Figs. 3 and 4. Theplates l5 have the extensions l6 and I! which are apertured to receivethe bolts l8, either one or both of the apertures being tapped toreceive the threads on the bolts. The upper end of each bolt I8 isattached to the machine screw l9. Each side 20 of the dryer has attachedthereto, the flanges 2| which are apertured to receive the bolts I8. Thewashers 22 space the heads of the screws l9 from the flanges 2|. and thenuts 23 are soldered to the bolts 18 so as to revolve therewith belowthe flanges 2|. By revolving the heads of the screws l9 with a a screwdriver, the position of the plates may be adjusted to suit anyparticular installation or operating condition.

The drying air projected through the nozzles tends to adhere to the webl4 and not only forms an insulating film adhering to the web but iscarried by the web from the dryer. The plates l5 extending close to theweb It scrape off, so to speak, the air film tending to adhere to theweb and guide the air so collected, and the other air between thenozzles, into the recirculated air chambers 8 at each side of the dryer.

Other functions of the plates I5 are that they cause air turbulence inaddition to that caused by the nozzles, providing the effect ofadditional nozzles without requiring additional air; they equalize thedrying efiect of the air by guiding'it across the web so that no part ofthe web dries before another part, and add to the efiiciency andcompactness of the unit by cutting down air and heat losses.

While it is preferred that the plates I5 extend passages 8 are reallyexhaust passages and could a v be used as such without recirculation.

A portion of the air leaving the web passes into the exhaust chamber 24below the web and out the exhaust passage 25 to the atmosphere. Thisvolume of exhaust air is, of course. equal, less such slight leaks asmay occur, to the volume of entering through the inlet 1.

While one embodiment of the invention has been described for the purposeoi! illustration, it should be understood that the invention is notlimited to the exact apparatus and arrangement of apparatus illustrated,as many departures therefrom may be suggested by those skilled in theart without departure from the essence of the invention.

What is claimed is:

1. A dryer comprising a casing, a plenum chamber In said casing, meansfor supplying heated air into said chamber, means'for supporting amoving web in its travel through said dryer, means including a pluralityoi nozzles each extending cross-wise said dryer and communicating withsaid chamber and converging towards said sup porting means for supplyinghigh velocity, heated air upon the web, means forming an exhaust passagein said casing at one transverse side of aid dryer, and transverseplates extending crosswise said dryer between adjacent nozzles andextending beyond the tips thereof adjacent the web, in planesintersecting the plane of the web, and extending to said passage, forpreventing air disnozzlesirom adhering to the moving web and for guidingthe air deflected from the web into said passage, said nozzles andplates extending along substantially the entire path of travel of theweb through said casing.

2. A dryer comprising a casing, a plenum chamher in said casing,

air into said chamber, means for supporting a means for supplying heatedextending crosswise said dryer from into said apparatus,

- ing the air deflected from moving web in its travel through saiddryer, means including a plurality of nozzles each extending cross-wisesaid dryer and communicating with said chamber and converging towardssaid supporting means ior supplying high velocity, heated air upon theweb, means forming exhaust air passages in said casing at the transversesides of said dryer, and transverse plates between adjacent nozzles andextending beyond the tips thereof adjacent the web, in planesintersecting the plane oi the web, and extending to said passages, forpreventing air discharged from the nozzles from adhering to the movingweb and for guiding the air deflected from the web into said passages,said nozzles and plates extending along substantially the entirepath oftravel of the web through said casing.

3. A dryer comprising a drying chamber for receiving a moving web to bedried, means for supporting a web for movement through said chamber, aplurality of nozzles spaced longitudinally and each extending crosswisesaid chamber above said means for projecting drying air upon the web,air moving and heating apparatus supported upon said chamber, a plenumchamber extending longitudinally of said chamber v above said nozzlesand connecting therewith, the

transverse sides of said plenum chamber being spaced from the oppositeside walls 0 said drying chamber for forming air recircu ation passages,means for supplying heated air from said apparatus into saidplenumchamber, means including substantially vertical ducts extendingoutside said chambers to the ceiling of said drying chamber in alignmentwith said passages and connecting therewith ior recirculating airtheretransverse plates extending crosswise said drying chamber to saidpassages and between said nozzles and extending beyond the tips of saidnozzles towards the web, in planes intersecting the planeoi' the web,and serving to prevent air discharged from the nozzles from adhering tothe web and for guidthe web into said passages and said ducts, and aduct above said ceiling, connecting with said ducts and said apparatus,for supplying air recirculated from said drying chamber to saidapparatus.

MILTON E. HANSON.

